#include<windows.h>
#include<stdio.h>

void DisplayError(DWORD dwError);

int main(int argc, char** argv) {
    HANDLE hf;
    DWORD dwLogCount;
    DWORD dwLogSize, dwReadByte, dwNextSize, dwError;
    EVENTLOGRECORD* pEventLogRecord = NULL;
    BOOL bResult;

    hf = OpenEventLogW(NULL, L"System");
    if (hf == NULL) {
        printf("Event Log Open Error.\n");
        return -1;
    }

    if (GetNumberOfEventLogRecords(hf, &dwLogCount))
        printf("Event Log Count %d\n", dwLogCount);
    else
        printf("Could not get Event Log Count\n");

    dwLogSize = 1024;
    pEventLogRecord = (EVENTLOGRECORD*)GlobalAlloc(GPTR, dwLogSize);
    if (pEventLogRecord == NULL) {
        printf("Memory Allocation Error\n");
        CloseEventLog(hf);
        return -1;
    }

    bResult = ReadEventLogW(hf, EVENTLOG_FORWARDS_READ | EVENTLOG_SEQUENTIAL_READ, 0, pEventLogRecord, dwLogSize, &dwReadByte, &dwNextSize);
    if (bResult) {
        printf("ReadByte : %d\n", dwReadByte);
    }
    else {
        dwError = GetLastError();
        DisplayError(dwError);
    }

    if (pEventLogRecord != NULL) {
        GlobalFree(pEventLogRecord);
    }
    CloseEventLog(hf);

    return 0;
}

void DisplayError(DWORD dwError) {
    LPTSTR lpBuffer;

    FormatMessage(
        FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
        NULL, dwError, LANG_USER_DEFAULT,
        (LPTSTR)&lpBuffer, 0, NULL);
    printf("%s\n", (char*)lpBuffer);
    LocalFree(lpBuffer);
}